Question

The data set below shows the number of books checked out from a library during the first two weeks of the month:

99, 29, 30, 42, 35, 36, 30, 35, 38, 43, 39, 40, 28, 31

Which of the following statements is true based on the data set?

There is one outlier, indicating very few books were rented out on that day.
There are three outliers, indicating very few books were rented out on those three days.
There are three outliers, indicating an abnormally large number of books were rented out on those three days.
There is one outlier, indicating an abnormally large number of books were rented out on that day.

Answer 1

There is one outlier, indicating an abnormally large number of books were rented out on that day.

Answer 2

There is one outlier, indicating very few books were rented out on that day.

Explanation:

Outlier is one which lies either below 1.5 (IQR) from Q1 or above 1.5 (IQR) from quartile III

Our entries are

99, 29, 30, 42, 35, 36, 30, 35, 38, 43, 39, 40, 28,

Minimum: 28

Quartile Q1: 30

Median: 35.5

Quartile Q3: 40

Maximum: 99

IQR = 40-30 = 10

1.5*IQR = 15

OUtliers are below 30-15 or above 40+15

Here only one entry 99 is there.

There is one outlier, indicating very few books were rented out on that day.